Diaminomethylenemalononitrile organocatalysts promote the asymmetric chlorination of simple cyclic beta-keto esters such as methyl, ethyl, and benzyl esters of 1-oxo-2,3-dihydro-1H-indene-2-carboxylic acid. This affords the corresponding chiral alpha-chlorinated carbonyl products in excellent yields with high enantioselectivities.
Chiral imidodiphosphoric acids were employed as catalysts for the enantioselective α-chlorination of β-keto esters and amides using NCS as the chlorine source, providing a series of optically active products with good to high enantioselectivities (74–95% ee) and excellent yields (92–99%). This represents the first report of the Brønsted acidcatalyzed enantioselective α-chlorination of cyclic β-keto
A simple and highly efficient N,Nâ²-dioxide organocatalyst system was developed for the asymmetric α-chlorination of cyclic β-ketoesters using easily available NCS as the chlorine source to provide a series of optically active α-chloro-β-ketoesters in excellent yields with 90â98% ee.
Simple Cinchona alkaloids serve as nucleophilic organocatalysts to facilitate the enantioselective α‐chlorination of β‐keto esters by using hypervalentiodine‐based Cl‐transfer reagents